Search results for " Road"
showing 10 items of 120 documents
Time reduction for completion of a civil engineering construction using fuzzy clustering techniques
2017
In the civil engineering field, there are usually unexpected troubles that can cause delays during execution. This situation involves numerous variables (resource number, execution time, costs, working area availability, etc.), mutually dependent, that complicate the definition of the problem analytical model and the related resolution. Consequently, the decision-maker may avoid rational methods to define the activities that could be conveniently modified, relying only on his personal experience or experts’ advices. In order to improve this kind of decision from an objective point of view, the authors analysed the operation correction using a data mining technique, called Fuzzy Clustering. …
A Mixed Approach for Determination of Initial Cable Forces in Cable-Stayed Bridges and the Parameters Variability
2015
The determination of initial cable forces in cable-stayed bridges is an important first step in design and analysis of the structure under external loads. Adjustments of stay forces are often required during construction in order to assure the requested behaviour of the bridge in terms of final geometrical configuration and internal force distribution. An accurate assessment of the stay tensioning system allows designers to obtain a good result at the end of construction, by considering the parameters involved as deterministic quantities, assuring the observance of the execution tolerances during works. Actual loads and their variations need instead a stochastic approach which can give usef…
Turbo-roundabouts vs Roundabouts Performance Level
2012
AbstractIn this paper the performance level of basic turbo-roundabouts and double-lane roundabouts are compared. Cowan's M3 headway distribution was chosen to take into account bunched vehicles moving along each circulating lane; the Hagring model was adopted to evaluate entry capacity both at turbo-roundabout and at double-lane roundabout.The comparative analysis was performed evaluating operational performances in terms of delay suffered by users entering the intersection.Results of the analyses show that efficiency of basic turbo-roundabouts highly depend on traffic situations and can be significant when major road captures most of the traffic demand.
Evaluation of the Safety Performance of Turbo Roundabouts by Means of a Potential Accident Rate Mode
2015
Turbo roundabouts are a particular road intersection layout, designed to increase the safety of double-lane roundabouts, while maintaining their excellent capacity. The main feature of this new concept of roundabout is the impossibility to move from one lane to another, provided by physical barriers marking the lanes. The paper shows an application to turbo roundabouts of a potential accident rate model, aiming to evaluate their safety improvement. Themodel is based on the concept of potential conflict: each vehicle involved in a general intersection performs a series of maneuvers which potentially imply a crash, according to the actual traffic. The number of accidents related to each criti…
Environmentally appraising different pavement and construction scenarios: A comparative analysis for a typical local road
2015
Abstract The aim of this work is to carry out a comparative analysis of environmental impacts for different scenarios of a typical local road. Life Cycle Assessment (LCA) is the modeling tool used to quantify and characterize comparative environmental impacts. In carrying out this specific application of the LCA, different road construction techniques were considered with regards to the whole structure and compared in order to identify the best alternative in terms of environmental sustainability. So far, in fact, typical LCA frameworks of roads have focused on recycled materials for pavement layers only, thus neglecting study of the materials used in the embankment or in the subgrade. In t…
Safety valuation methods at urban atypical intersections. Analysis of infrastructural scenarios
2007
The definition of decision support tools for identifying ex ante evaluation issues for road safety measures is a new challenge for policymakers and designers managing road networks with the intention of improving traffic safety for roads of their competence. This is consistent with explicit strategies on sustainability in the transport sector established at European level, considering road safety as an essential prerequisite to warrant a sustainable mobility. Based on these considerations, the need for evaluation instruments of safety conditions both for existing infrastructural schemes and for new road installations is recently arisen so that the identification of risks involved in a parti…
Urban public transport optimization by bus ways: a neural network-based methodology
2007
This paper describes an approach for planning the introduction of bus lanes into the urban road network, that has been applied to the urban area of Palermo. The proposed modelling tool adopts a multi-agent objective function expressing the trade-off between the interests of diverse stakeholders: the generalized transport cost for car drivers and the travel time for public transport users. The reaction of car traffic to a certain planning scenario has been simulated by the DUE assignment technique and the positive impact of the modal shift on the objective function has been tackled by attaching a suitable weight to the time saving for bus passengers. The rise in the bus travel speed, owing t…
How to formulate an accident prediction model for urban intersections.
2009
Several safety prediction models and methods have been developed to eliminate the relationship between the expected accident frequency and various urban intersection geometry and operational attributes. It is generally accepted that accident rates tend to be higher at intersections than on through sections of a road. This is particularly frequent in urban area where roads are characterized by intersections in close succession; moreover, the safe and effective operations of the urban road system can be significantly affected by safety conditions at intersections. In this paper models and methods designed to understand and to predict the accident process at urban intersections are reviewed. I…
ROAD project: Robotics for assisted diving
2014
The activities associated to underwater diving are of great importance in many areas. In the second half of the last century, diving technologies have greatly progressed, but diving is still characterized by significant risks, especially for professional divers who works at high depth, and limited practicability. The use of robotic systems and automatic procedures would allow, as in other situations where safety is of concern (for example, in case of hazardous works or in relation to hostile environments), a reliable monitoring and assessment of the physiological conditions of human operators during their activities. Moving from currently available technologies in underwater robotics, the R…
Risk Indicators and Road Accident Analysis for the Period 2012–2016
2017
Road accidents are a major societal issue for every country. The purpose of this paper is to assess the number of traffic and road accidents depending on a series of variables (collision mode, road configuration, conditions of occurrence, road category, type of vehicle involved, personal factors, and length of time of the driving license) in Romania from 2012–2016. The analysis of the road accident trend identifies the causes of accidents, road safety performance indicators, and risk indicators. Having these identified data, a framework is proposed for improving the road safety system and reducing accidents. The Romanian Police, the National Institute of Statistics (NIS) in Romania, and the…